Power-hammer.



G. D. ROBERTS.

POWER HAMMER.

APPLIGATION FILED B321. 3, 1908.

989,051 Patented Apr. 11,1911.

3 BHEETB-BEEET 1.

A TTORNB v5 n4: NORRIS PETERS co., wumusmu, n g

G. D. ROBERTS.

POWER HAMMER.

APPLICATION rlnnn arm. 3, 100a.

Patented Apr. 11, 1911.

3 BHEETBSHBET Z.

INVBNTOR ATTORNEY 1n: NORRIS PETER! co, wumlvcrou. n. c.

G. D. ROBERTS. rownn 1111111113. APPLIOA TIOH FILED SEPT. 8, 1908.

989,051 Pa11en 11ed Apr. 11, 1911.

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"fITNESSES: I I.

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GRIFFITH D. ROBERTS, F COLUMBUS, WISCONSIN.

POWERHAMMER.

Specification of Letters Patent.

Application filed September 3, 1908.

Patented Apr. 11, 1911.

Serial No. 451,549.

To all whom 'it may concern:

Be it known that I, GRIFFITH 1). Ron- ERTS, residing. in Columbus, in the county of Columbia and State of lVisconsin, have invented new and useful Improvements in Power-Hammers, of which the following is a description, reference being had to the accompanying drawings, which are a part of this specification.

The invention has relation to improvements in power hammers, particularly adapted for use in machine shops for hammerlng and shaping metals, or for welding metals together, etc.

The primary object is to provide a construction wherein a plurality of pistons arranged within a cylinder are provided, said pistons being disconnected from each other, and one of said pistons by its reciprocation adapted to operate another of said pistons, the latter piston having the hammer-head connected therewith.

A further object is to provide a construction wherein the bowl of the hammer may be readily graduated to produce heavy or light blows, through the medium of vacuum producing mechanism.

A further object resides in the provision of means, in connection with the attainment of the last described object, whereby the hammer may be quickly brought to a complete stop, and securely held until such time as it is desired to resume the hammering operation.

Withthe above primary, and other incidental, objects in view, the invention con sists of the devices and parts, or the equivalents thereof, as hereinafter more fully set forth.

In the accompanying drawings, Figure 1 is a side elevation of the machine, parts in section; Fig. 2 is an elevation of the opposite side; Fig. 3 is a front elevation; Fig. 4: is an enlarged detail view, parts broken away, of the locking and unlocking mechanism for the lower piston; and, Fig. 5 is a horizontal section of Fig. 1, on the line 55 of said figure.

The mechanism may be supported by any desirable form of frame. I prefer, however, to provide the framework shown in the accompanying drawings, and comprising a base portion 6 and an upwardly extending standard 7. The top of the forwardly projecting portion of the base forms a bed to which is secured the anvil 8.

Secured to and extending upwardly from the top of the standard 7 is a bearing 9 for a horizontal shaft 10. The rear end of this shaft has an additional bearing 11 formed at the upper end of an arm 12 outstanding from the rear of the standard, and secured thereto by means of bolts, as clearly shown in the drawings. On the rear end of shaft 10, jlust in advance of the bearing 11, is rigic ly mounted a belt wheel 13, around which passes a belt (not shown) leading from any suitable source of power. On the opposite, or forward end, of the shaft is rigidly mounted a disk 14: provided with an eccentric crank 15, to which crank the upper end of a connecting rod 16 is pivotally connected.

Secured to the front side of the standard 7 is an air cylinder 17, said cylinder provided with a bottom piece, but open through its top. The cylinder may be secured to the standard in any desirable manner, but I prefer to provide the rear side of the cylinder with transverse brackets 18-18, through which bolts 19 are passed and enter the standard. The lower end of the connecting rod 16 extends through the open top of the cylinder, and is pivotally connected to an upper piston 20, reciprocable in the cylinder. Below the upper piston, and entirely disconnected therefrom, is another piston 21, which is also reciprocable in the cylinder. Extending downwardly from piston 21 and through an opening 22 in the bottom of the cylinder is a hammer-stem or handle 23, formed or provided at its lower end with a hammer-head 24, said head being in vertical alinement with the anvil 8. The front edge of the hammer-stem is formed or provided with a series of ratchet teeth 25 which are adapted to be engaged by the rear end of a pawl or dog 26, said pawl or dog being movable in a guideway 27 extending forwardly from the lower end or bottom of the cylinder. Extending upwardly from the forward end of the pawl is an arm 28, the upper end of said arm having a branch 29 extending rearwardly therefrom at right angles thereto. This branch arm is slotted longitudinally, as indicated by the numeral 30. The side walls of the slot support the ends of a transverse axial pin 31, on which is mounted a roller 32. The rear end of branch arm 29 is adapted to move and to be guided in an opening 33 formed at the u per end of an arm 34 extending upwardly rom connected the outeriend of a'coiledspring 42, theinner end of said coiled spring being 'connectedto the side of the base 6.

the guide 27, and said rear end of branch arm 29 has projecting rigidly therefrom a rearwardly extending rod35 which is encircled by a coiled spring 36 hearing at one end against the upper end of arm 34, and at its opposite end against a pin intersecting the rear end of the rod.

Extending along one side-of the base of the frame is a rock shaft 37, said shaft being journaled in suitableibearings 3838. This shaft has extending.upwardly-therefrom a lug 39,to' which-lug is connected the upper 611Cl'0f a depending foot treadle140. The rock shaft has also dependingtherefrom an arm :41. To the lower end of this arm is 1 Extending'inwardly from rock shaft 37 is a'icrank 43,.and to the inner end of this "crank is pivotally connected a link 44. The .upper'endof this linkzarticulates with or is jointed to the rear endKof a lever 45. I This 7 lever is pivoted. or fulcrumed between its .of the drawing. upwardly from lever 48 is a link '54. The upperend of link-54 is pivotally connected ends'onthe piVOt pin 46. The forward end of lever 45 is jointed or pivoted to a vertical link 47', and the :upper end of said vertical link is pivoted. to one-.end of a horizontal -lever'48,-.said horizontal leverhaving itsrop- 'positeend pivoted to the. standard 7 on a .pivot pin 49. Thehorizontal lever passes between and isguided by two curved brackets' or. frames 50 50, 'asmost clearly shown in Figs. 1 and 3. These brackets arecon- -nected-by transverse pins '5050 which serve tolimit the up and down movement of lever 48. 'A pin 51 extends downwardly .fromiever48 and freely through 'an elongated-slotformed in a laterally projecting arm 52. A coiled spring 53 encircles this pin, and is confined between the lever 48' and the arm 52,- and serves to normally maintain lever: 48 in the position shown-in Fig. 3 Pivoted to and extending to oneend of a lever 55, the opposite end of said leverbeing pivoted to an-arm'56. At a pointbetween its ends the lever 55 has pivotally connected thereto and depending therefrom avalve rod 57 said valve rod extending into a valvechamber 58 provided in apipe 59, and provided within said chamher with a valve (not 1 shown)" adapted to open and. close thepassage in the pipe 59.

The-inner end of pipe 59 connects to an opening '60 in thecylinder 17, said opening being located about midway of the forward portion'ofthe cylinder so as'to communicate with the spaceof the cylinder "confined be- .tweenthe two pistons 20 and 21.

Extending forwardly from the lever 48, at a point between; the ends of said lever is apin 61', and connected to the outer end of .said pinand'depending therefrom-is an arm said pawl from engagement "ratchet' teeth 25' of the; hammere'stem or The rotation of-said shaft will cause a reciprocation of the upper piston 20 in thecylinder 17 It will be understood that the valve which controls the passage in pipe 59 is normally open, and solong'as it remains in its open position the up and down movement of piston 20 has no effect whatever onthe lower piston 21', said lower "piston being adapted tobe maintained in position with the hammer-headra-ised above-the anvil 8 by'means of the engagement of the pawl 26 with the ratchet teeth 25. If, now, itis desired to "operate themechanism for the purpose of hammeringmetal, or welding metal together,

the said metal is placed over the anvil 8. Pressure is now exerted on the foot treadle 40. This pressure will cause the rock shaft 37 to rotate in a direction to push upwardly on the link 44. The upward movement of this link will cause a turning of the lever 45 in a direction todepress its forward end.

The depressionof the forward end of lever 45 causes a down pull on'link 47, :and by reason of the connection between the upper end of link 47 and the lever '48, the said lever 48 is turned downwardly on its pivot.

The down movement of lever 48 causes a like movement of arm '62, and the cam edge 63 of this arm is thereby brought into engagement with the roller 32, with the result that at the very startofthe down movement of lever 48 arm 62 is operatedso as to=bring its cam edge against roller-32 and thereby force arm 28 in the direction of the arrow,

Fig. 4. The movement of arm 28 inthis direction-causesan outpull on-pawl 26, and a consequent withdrawal of the inner endof with the handle 23, whereby the piston 21, stem 23 and. hammer-head -24arefreleased, the said p ston being thereby-rendered free to be re iciprocated in'thecylinder. Therdown movement of lever 48' also causes adown pull-on llnk 54, and by reason ofthe'connection of sald l1nk with the lever 55, the said lever is turned downwardly'on' its pivot, and the valvestem 57 thereby forcedadownwardly into the-valve "chambero58, the :said down -movement of the. valve stem: forcing the valve to aclosing position. Ifthe. foot treadle is depressed to its-zfullrextent, the valve will be:entirely*closed,so-as to fully shut ofi? the passage inpipe:59. -When-the valve is in this osition, and when the pisten 20 in its reciprocation moves upwardly in the cylinder a suction is created in the space ofthe cylinder between pistons 20 and 21, and hence a vacuum is formed, with the result that as the upper piston moves upwardly, the lower piston 21 is simultaneously drawn upwardly. On the succeeding down stroke of the piston rod 16 the piston 20 is necessarily forced downwardly in the cylinder, and hence the lower piston 21 is permitted to drop by gravity, and by the pressure of the air interposed between the pistons against said lower piston. In this manner hammer-head 24: is brought into forcible engagement with the metal which is placed on the anvil 8. With the continued rotation of the shaft 10 this operation is repeated, foot pressure of course being maintained on the foot treadle 40. When it is desired to stop the operation of the hammer, foot pressure is removed from the foot treadle 40, and the several links and levers through the medium of the springs 53 and 42 are thereby restored to their normal positions. The very first movement of lever 48 toward this normal position causes an uplifting of arm 62 and consequently retracts said arm so that its cam edge 63 no longer operates upon the roller 32. WVhen this occurs the coiled spring 36 expands, and draws pawl 26 inwardly into engagement with the ratchet teeth 25, and thereby holds the piston 20 stationary.

If instead of entirely removing pressure on foot treadle 40, the pressure thereon is decreased, then the valve will partially close the passage in pipe 59, and thereby reduce the suction exerted by the piston 20 in its upward travel. Said piston under such circumstances would therefore have the effect of lifting lower piston 21 a less distance than when the valve is entirely closed, and consequently reduce to that extent the distance the hammer-head 24: has to drop, the force of the blow being thereby reduced. It will be readily apparent from this that the force of the blow may be graduated so as to produce a heavy blow or blows of less force, dependent upon the extent the foot treadle 40 is depressed.

It will be observed that by my construction, wherein the lower piston 21 is entirely independent of, and disconnected from the upper piston 20, a yielding blow of the hammer-head is permitted, inasmuch as when said hammer-head comes in contact with the metal an up movement of the piston 21 within the cylinder is permitted. This, it will be observed, is closely allied to the action of a hammer in the hand of a person, which, when the head thereof strikes an object, will rebound.

It will be evident from the foregoing description that I provide a simple form of mechanism wherein the operation of hammering is accomplished through the medium of a vacuum producing mechanism, which creates a vacuum between the two pistons, when the valve is at a closing position, and that this vacuum or suction can be decreased at will so as to provide for graduating the force of the blow delivered by the hammerhead, it being evident that the greater the extent or area of the passage in the pipe 9, the less the extent of the vacuum created, and that the extent of the up movement of the lower piston, and consequent drop of the hammer, and force of the blow thereof, is dependent upon the extent of the suction or vacuum produced.

WVhile I have specifically shown and described an air opening in the cylinder, yet I do not wish to be understood as specifically limiting myself to said opening, inasmuch as successful results could be obtained without the provision of said opening, as it is obvious that, with the omission of the opening, the upper piston, during its up stroke, would create a suction and consequent vacuum, and thereby draw the lower piston upwardly. Under this construction, however, in order to stop the operation of the mechanism, it would be necessary to stop the rotation of the shaft 10. Also, successful results might be obtained by the provision of an opening in the cylinder without the use in conjunction therewith of the valve mechanism. The construction shown in the drawings, and specifically described in the specification, however, is the preferred construction, and the one which practice has demonstrated is the more desirable construction.

What I claim as my invention is;

1. In a power hammer, the combination of a rigidly and immovably supported cylinder provided with a valve-controlled opening, pistons in the cylinder disconnected from each other, one of said pistons carrying a hammer head, means for positively and continuously reciprocating one of said pistons, means for operating the valve to control the flow of air through the air opening of the cylinder and into the space between the pistons, means for releasably locking the piston which carries the hammer head during the time the valve isin an open position, and while the other piston is reciprocating, and means for releasing said locking mechanism to permit of the reciprocation of the hammer-carrying piston with the reciprocation of the continuously operating piston, and when the valve is operated toward or to a closing position.

2. In a power hammer, the combination of a rigidly and immovably supported cylinder provided with a valve-controlled opening, pistons in the cylinder disconnected from each other, one of said pistons carrying a hammer head, means for positively and continuously reciprocating one of said pistons,means for operating the valve to -contro'l the flow of air through the airopen- -ingofthe cylinder and into thespace be tween the pistons, means for automatically and releasably locking the piston which car- 'ries -the hammer head during the time the valve is in an open position,'and whilethe other piston is reciprocating, and means for automatically releasing said locking mechanism to permit of the reciprocation of the hammer-carrying piston with the reciproca tion of the continuously opera-ting piston, and when the valve is operated toward or to a closing position.

' 35in a power hammer, the combination of a suitably supported cylinder having a valved opening, a piston in the cylinder, -means for reciprocating said piston, another pistonin the cylinder and disconnected from the first referred to piston, and having a hammer-sternon handle connected thereto and projecting out through one end ofthe cylinder, and provided with a series of ratchet teeth, a hammer-head at the end of saidstemorhandle, and in line with the anvil, and a pawl ordog adapted to engage with andbe disengaged from the ratchet teeth.

4. In a power hammer, the combination of a suitably supported cylinder provided with a valve-controlled air opening, mechanism for operating the valve to close or open the air opening, a piston in the cylinder, means for reciprocating said piston, another piston in the cylinder-and disconnected from' the first referred to piston, and having a hammer-stem or handle connected thereto and projecting out through one end thereof, 'and'provided with a series of ratchet teeth,

hammer-head at the outer end of said StBllfi or handle, a pawl or dog, and -mecha n-ism connected to said pawl or dog and control led by the valve-operating mechanism, and adapted, when said valve operating :mechanism is opera-ted to open the valve, to be actuated so'as to force the pawl or dog into engagement with the ratchet teeth, and,

disconnected from each other, said cylinder air opening communicating with the space between the two pistons, means for positively reciprocating one of said pistons, a hammer connectedto the other "of said pistons, a'*rock-"shaft mounted 'in hearings in the frame, a systemof levers-and links-between the rockshaft andi the valve stem'of the *valve and normally holding the valve in an open position, means "for operating-the rock shaft,- said means when operated acting of a suitably supported cylinder, said'cylinder provided with a valve-controlled-air opening, pistons withinthe cylinder anddisconnected from each other, said cylinder air opening communicating with thespace between the-two piston," one ofsaid pistons having a hammer stem or handle'projecting therefrom and through one end of the cylinder, said stem or handle provided with ratchet teeth, a hammer-head connected to the outer end of the stem or .handle,'mea11s for positively reciprocating the other" of said pistons, a pawl-or dog normally engaging the ratchet teeth of the hammer-stem or handle and thereby holding the piston thereof against movement, a rock shaftmounted in hearings in the frame, a systemof levers and links connecting the rock shaft with the pawl or dog and with the valve stem of the valve, and adapted to normally holdthe pawl or dog in engagement with'the ratchet teeth, and normally to hold the valve in an open position, means for operating the rock shaft, said means when operated acting upon the levers and links and causing the withdrawal of the pawl or dog from engagement with the ratchet'teeth, and causing the valve to be forced to a closing position, and means, when power is removed from the rock shaft-operating means, for returning the levers and links to normal position-and thereby returning the pawl or dog to locking engagement with the ratchet teeth, and returning the valve to an open position.

7. In a power hammer, the combination of a suitably supported cylinder provided with a valve-controlled air opening, pistons within the cylinder and disconnectedfrom each other, said cylinder air opening communicating with the space betweenthe two pistons, means for positively reciprocating, one of said pistons, a hammer-head connected to the other of said pistons, a rock shaft mounted in bearings'in the frame, said rock shaft provided with a'projecting crank, a link pivotally connected at one end to said crank, a medially pivoted lever to one end of which the opposite end of the link is connected, another link to one end of which the opposite end of the medially pivoted lever is connected, another lever pivoted atone end and having its opposite end pivotally connected to the opposite end of the latter link, a I

third link having one end connected to said last mentioned lever, a valve-stem operating lever pivoted at one end and having its opposite end connected to the opposite end of the third link, a valve stem extending from the latter lever, and adapted to operate the valve, the said valve being normally held in an open position, means for operating the rock shaft, said means when operated acting upon the levers and links and causing the valve to be forced to a closing position, and means, when power is removed from the rock shaft operating means, for returning the valve to an open position.

8. In a power hammer, the combination of a suitably supported cylinder provided with a valve-controlled air opening, pistons within the cylinder and disconnected from each other, said cylinder air opening communicating with the space between the two pistons, means for positively reciprocating one of said pistons, a hammer-head connected to the other of said pistons, a rock shaft mounted in hearings in the frame, said shaft provided with a projecting crank, a link pivotally connected at one end to said crank, a medlally pivoted lever to one end of which the opposite end of the link is connected,

another link to one end of which the opposite end of the medially pivoted lever is connected, another lever pivoted at one end and havingits opposite end pivotally connected to the opposite end of the latter link, frames or brackets between which the latter lever is guided, said frames or brackets connected by transverse pins spaced a distance apart and serving as stops to limit the extent of the movement of said lever in opposite directions, a thirdlink having one end connected to the said last mentioned lever, a valve-stem operating lever pivoted at one end and having its opposite end connected to the opposite end of the third link, a valve stem extending from the latter lever and adapted to operate the valve, the said valve being normally held in an open position, means for operating the rock shaft, said means when operated acting upon the levers and links and causing the valve to be forced to a. closing position, and means, when power is removed from the rock shaft operating means, for returning the valve to an open position.

9. In-a power hammer, the combination of a suitably supported cylinder having a valved opening, pistons within the cylinder and disconnected from each other, means for positively reciprocating one of said p-istons, a hammer-stem or handle connected to the other of said pistons and projecting out through one end of the cylinder, said stem or handle provided with ratchet teeth, a hammer-head at the outer end of said stem or handle, a pawl or dog normally engaging the ratchet teeth, the said pawl or dog provided with a projecting arm, said arm having a longitudinally slotted branching arm extending therefrom at an angle thereto, a spring encircling said branching arm and normally acting to hold the pawl or dog in engagement with the ratchet teeth, a pin supported in the walls of the slot of the branching arm, a roller mounted on said pin, a rock shaft mounted in bearings in the frame, said shaft provided with a projecting crank, a link pivotally connected at one end to said crank, a medially pivoted lever to one end of which the opposite end of the link is connected, another link to one end of which the opposite end of the medially pivoted lever is connected, another lever pivoted at one end and having its opposite end pivotally connected to the opposite end of the latter link, an arm extending from the latter lever and having its free end in the form of a cam and entering the slot of the branching arm and adapted when the lever to which it is connected is moved in one direction to act against the roller, means for operating the rock shaft, said means when operated acting upon the levers, links, and the projecting cammed arm, to thereby cause the cam edge of the said arm to act on the roller and effect the withdrawal of the pawl or dog from engagement with the ratchet teeth.

10. In a power hammer, the combination of a suitably supported cylinder having a valved opening, pistons within the cylinder and disconnected from each other,-means for positively reciprocating one of said pistons, a hammer stem or handle connected to the other of said pistons and projecting out through one end of the cylinder, said stem or handle provided with ratchet teeth, a hammer head at the outer end of said stem or handle, a longitudinally movable pawl or dog normally engaging the ratchet teeth, the said pawl or dog provided with a projecting arm, said arm having a branching arm extending therefrom at an angle thereto, a spring encircling the branching arm and normally acting to hold the pawl or dog in engagement with the ratchet teeth, and means adapted to act on the branching arm against the contrary power exerted by the spring, to thereby force said branching arm, together with the arm from which it branches, in a direction to carry the dog or pawl out of engagement with the ratchet teet 1.

11. The combination of a cylinder, a valve-controlled pipe entering said cylinder and in communication therewith medially of its length, a rock-shaft mounted in suitable bearings, said shaft provided with a projecting crank, a link pivotally connected at one end to said crank, a medially pivoted lever to one end of which the opposite end of the link is connected, another link to one end otwhich the opposite end of the. me-

dially pivoted-lever is connected, another leverv pivoted at one endand having its oplever, a valve-stem operating lever pivoted at .one end and having its opposite end connected tothe opposite end of the third link,

a valvestem extending fromthe lat-terlever and adapted to operate the valve: mecha-. nism of the valve-controlled pipe, the said valve: member being normally held in an openposition,-means for operating the rockshaft, the said means when operated acting upon .the leversand linksv to thereby cause the. valve to be forced to a closing position, and means when power is removed from therock-shaftoperating means for returning. the valve to an open position.

12, The combination: of a cylinder, a valve-controlled pipe entering said cylinder and vincommunication therewith medially of .its.length, a rock-shaft mounted in suitable bearings, said shaft provided with: .a projectingcrank, a link pivotally connected at one. endto said crank, a medially pivoted lever to one. endof which the opposite end ofthelink is connected, anotherhlink to one end of which the opposite end of the mediallypivoted lever is connected, another lever pivoted at one endand having its opposite end pivotally'connected to the op-- posite end of thelatter link, stops for limiting the extent of movement .of this lever in either direction, a third link having one Copiesofthispatentsmay be obtained for five cents each, by addressing the Commissioner of Patents,-

end connected to. the last .mentionedlever, a valve-stem: operating lever pivotedat onev end and having .its opposite end connected to the opposite end of the third link, a valve the said means when operated acting upon the levers and links to thereby cause the valve.

to be forced to a closing position, and means when power is removed from the rock-shaft operating means for returning the. valve to anopen position.

13. In a pneumatic hammer, the combination of a cylinder, a primary piston slidable within said cylinder, means for reciprocating sald primary -p1ston,.a secondary piston slldable within said cylinder, a rod icon-.

nected with. said secondary. piston, a toothed barsecured on said rod, a latch adapted to engage with the teeth of said toothed barto support said rod, ,a valve communicating with the :1I1t61l0l space of said cylinder be.-. tween the cyllnders, means for normally keeping said valve open,.and means for re-.

tracting said latch simultaneously with then closingv of said valve.

1n testimony whereof, ,I afiix my slgnature, 1n presence of two witnesses.

D. R. ROBERTS, Gr. C. GRISIM.

Washington, D. G. 

